The present disclosure relates generally to power plants and, more specifically, to systems and methods for testing flue gas cleaning systems.
At least some known power plants generate energy derived from the combustion of carbon and hydrogen-containing fuels such as coal, oil, peat, waste, biofuel, natural gas, and the like. In addition to carbon and hydrogen, these fuels may contain oxygen, moisture, and contaminants. As such, the combustion of such fuels results in the production of a gas stream containing the contaminants in the form of ash, carbon dioxide (CO2), sulfur compounds (often in the forms of sulfur oxides, referred to as “SOx”), nitrogen compounds (often in the form of nitrogen oxides, referred to as “NOx”), chlorine compounds (often referred to as “HCl”), mercury, and other trace elements.
Known power plants may use capture systems to facilitate removing the contaminants from the gas stream, prior to releasing into the atmosphere. For example, some known flue gas desulfurization (FGD) systems include multiple components that facilitate removing or scrubbing sulfur compounds and other acid gases from the gas stream of power plants. Some of such known FGD systems, for example, use a calcium-based reagent, such as calcium hydroxide (lime) to react with the sulfur compounds and other acid gases within the gas stream to form solid particles, such as calcium sulfite, which then may be extracted from the gas stream. Moreover, at least some of these known systems are semi-dry systems that at least partially recirculate the reagent. For example, some known semi-dry FGD systems recycle the solid particles by mixing the particles with fresh reagent and hydrating the mixture before injecting it into the gas stream. Once in the gas stream, water within the mixture evaporates and the resulting solid particulates are flash dried to be recirculated within the system.
Such semi-dry systems generally increase in efficiency as a temperature of the gas stream is lowered, however, there is a lower temperature limit, such as a condensation temperature, which agglomeration of the hydrated solid particulates results in caking or pelletization, which may stress the components of the recirculation system. In at least some applications, the lower temperature limit is dependent upon a large number of environmental factors and operating conditions, and is difficult to indirectly predict or derive from external measurements because there are many different parameters that affect agglomeration of the particulate matter within the flue gas desulfurization systems. Thus, at least some of such systems either operate at an increased temperature to ensure the lower limit is not reached when conditions change, thus decreasing efficiency, or alternatively operate at a temperature that may undesirably slip below the lower temperature limit in response to changing conditions, which may result in increased agglomeration and stress on the recirculation system.